Northern pike research at Wanahoo, Flanagan tells opposite stories - Lincoln Journal Star
Fisheries biologists for the Nebraska Game and Parks Commission study northern pike at Lake Wanahoo and Flanagan Lake each spring to assess their status. What they found in 2023 are pike fisheries headed in opposite directions.
The work, known as mark-and-recapture tagging, looks at the overall health of the pike populations and is the only way biologists know if management action is needed.
"Through sampling, we gain knowledge on relative population size as indicated by catch rates (fish caught per net per night) and size structure, and can gauge the health of individual fish," said Jake Werner, southeast district fisheries biologist for Game and Parks.
Flanagan, which opened in Omaha in 2018, has been sampled annually since 2021. It saw its highest catch rates yet, 3.02 pike per net, as well as the largest pike yet sampled there, 38.7 inches long. In total, 362 pike were captured over five days, most in the 20- to 28-inch range.
People are also reading…
"The northern pike fishery at Flanagan Lake is developing nicely and should provide ample opportunities for anglers targeting pike," Werner said.
Wanahoo has been sampled every year since it opened outside Wahoo in 2012. This year, 233 pike were netted over four days, the second-lowest catch since the study began. Most fish were 20- to 28-inchers, the largest measuring 38.2 inches.
"Overall, the pike fishery at Wanahoo has been declining since 2016 due to multiple factors, such as the presence of common carp, degraded water quality, lack of aquatic vegetation and siltation of the north end of the lake," Werner said.
Since Wanahoo and Flanagan have been open, northern pike have always had a catch-and-release restriction, with the intent of keeping fish in the lake so more people can catch them.
But it doesn't come easy. The northern pike populations at the lakes are maintained by periodic stocking because there is little evidence of natural recruitment. Though more difficult, the hatchery must raise pike to 10 to 12 inches for these lakes; fish stocked at a smaller size would be susceptible to other predator fish in the lakes.
Pike are sampled in March, soon after ice is off the lake, because they are easier to capture in shallow, vegetated areas where they move to spawn.
Twenty or 30 trap nets needed for sampling are set from boats the first day of sampling by fisheries staff. The following morning, staff members meet volunteers at the lake. They split into two groups and go out in boats to check nets in different parts of the lake.
The nets are pulled onto the boat, fish are sorted and any northern pike are put into a live well. Other fish are immediately returned to the lake.
Outdoors calendar, 6/11
Each northern pike is measured. A pike caught for the first time will get a tag with a unique identification code and have that number recorded before being released. Numbers also are recorded from pike that had been caught and tagged in previous years. Each net is reset at the same location and the process is repeated for four or five days.
When the operation is complete, biologists gather the nets, return to the office and compare the current length of recaptured fish to that of previous years and calculate the average number of fish they caught in each net. This provides an overall population estimate and lets them track the growth of individual fish.
While Game and Parks samples fish around the state, this mark-and-recapture study gives them a much more detailed look at the northern pike population in these lakes.
Comments
Post a Comment